docs: def _get_files_generator(src_dir, files_list):
      """
      A generator which populates and return a dict.
  
      :param src_dir: A string containing the source directory.
      :param files_list: A list of dicts containing the src/dst mapping of files
       to overlay.
      :return: dict
      """
      if files_list:
          for d in files_list:
              yield {
                  'src': os.path.join(src_dir, d['src']),
                  'dst': _get_dst_dir(d['dst']),
                  'post_commands': d.get('post_commands', []),
              }